1. Field of the Invention
The present invention relates to an image pickup system that includes an image pickup apparatus for picking up an image of a subject and outputting an image pickup signal of the image and a signal processing apparatus having a signal processing circuit for processing the image pickup signal inputted from the image pickup apparatus, and a method for maintaining the image pickup system.
2. Description of the Related Art
In the medical and other fields, so-called electronic endoscope apparatuses have been widely used, each of the apparatuses being provided with a charge coupled device (CCD) as a solid-state image sensing device at a distal end portion of an insertion section of the endoscope, and the CCD is used to pick up an image of a subject and the image from the endoscope is displayed on a monitor. Generally, the electronic endoscope apparatus is configured so that an analog image pickup signal from an electronic endoscope that has a CCD therein is transmitted to an external processor connected to the electronic endoscope so as to be exposed to various processes. That is, an image pickup apparatus for picking up an image of a subject and outputting an image pickup signal of the image outputs an analog image pickup signal, which is digitalized for processes in a signal processing apparatus.
To the contrary, a so-called electronic endoscope is known, in which for downsizing of a signal processing circuit, a part of the signal processing circuit is mounted to the endoscope, and an analog image pickup signal from a CCD is converted to a digital image pickup signal before the signal is outputted to an external processor which is a signal processing apparatus.
For example, Japanese Patent Application Laid-Open Publication No. 2006-288753 discloses an electronic endoscope system that has an endoscope with a CCD and an external processor removably connected to the endoscope, and the endoscope is provided with a digitalizing section that digitally processes a signal captured by the CCD, a data compressing section, a data transmitting section, and the processor is provided with a data receiving section, and a data decompressing section.